A couple of weeks ago I was invited to a presentation by Scott Ambler on "Scaling Agile Software Development: Strategies for Applying Agile in Complex Situations", it was an interesting talk. He showed a lot of diagrams and stats from a 2008 Agile Adoption rate survey, you can find the info here. The survey results are for example agile adoption rates, success rates, increase / decrease in code quality and costs. The problem with the survey is that it does not include any definition of what qualifies as agile. There are many different definitions on what makes software development agile, and many definitions like the manifesto (if you can even call that a definition) are very vague. I am not saying there is anything wrong with the manifesto or that agile needs to be better defined, what I am saying is that because agile can mean a lot of things to different people, and that many think they are doing agile while others might heartedly disagree, makes agile surveys like this very hard to interpret.

Traditional teams are equally as likely to create deliverable documentation.

For all the talk in the agile community about acceptance test driven development, few teams are actually doing it in practice.

etc..

Without some minimum criteria for what qualifies as "doing agile" these surveys don't tell me that much. Even if I would disagree with the definition I think they would make surveys like this a lot more interesting.

I am not saying that the surveys are worthless, they do tell you something and they are a great resource for convincing management of agile practices so it is great that someone is taking the time to make them.